FIG. 1A is an exploded view of an edge-lit backlight model 100 in the prior art. As shown in FIG. 1, the edge-lit backlight model 100 comprises a back board 101 and a heat sink 103 attached to the back board by screws 102. An LED light bar 104 is attached to, and perpendicular with the heat sink 103. A plurality of LED 105 is arranged on the LED light bar 104.
FIG. 1B is a cross-section view of the edge-lit backlight model in the prior art. As shown in FIG. 1 and FIG. 2, the edge-lit backlight model 100 further comprises a light guiding plate 106. A locating pole 107 is attached to, and perpendicular with the back board 101. The light from the LED 105 is projected onto the panel (not shown) after passing through and effected by the light guiding plate 106.
In the edge-lit backlight model 100, the distance between the LED 105 and the light guiding plate 106 will influence the efficiency of light coupling by the LED 105 to the light guiding plate 106, the shorter the distance, the higher the efficiency of light coupling and the efficiency of the whole edge-lit backlight model 100 will be improved.
FIG. 2 is a cross-section view of the edge-lit backlight model 100 in the prior art, wherein the light guiding plate 106 is expanded. As shown in FIG. 2, when the operating environment of the edge-lit backlight model 100 is changed, especially the light guiding plate 106 is expanded for being heated or being moistened, the light guiding plate 106 may contact with the LED 105 due to expansion and deformation. There are two risks resulted from the deformation, the first, LED 105 will be damaged by impact and press of the light guiding plate 106; the second, the light guiding plate 106 is fixed by the locating pole 107 and can not extend along the width direction, which will result that the light guiding plate 106 is bent.
An adequate moving space is usually pre-arranged and the distance between the light guiding plate 106 and the LED 105 is largened, so as to prevent the light guiding plate 106 from being bent due to heated or moistened, but the light coupling distance will be largened and the efficiency of backlight will be influenced significantly.